jim lehrer of pbs is prepared to moderate. andrea mitchell joins us now from denver. you know, they have three debates coming up. we're hearing that tonight's is going to be the most important. why is that? >> reporter: well, it's the first. wendy, this is the first chance we have to see these men face to face. they've been trading charges back and forth as well as their surrogates through speeches, stump speeches and also the campaign advertisements. this is going to be the first time they challenge each other. this format is designed to let them do exactly that. you'll not have opening statements. there are two-minute closing statements from each of them. but they'll be able to question each other, all on domestic policy. but we're told mitt romney does want to try to bring benghazi into the mix. they think there's an opening there to weaken the president by what went wrong in libya by that fatal attack. >> the race has tightpened nationally a little bit. two of the three battleground states is a statistical tie at this point. yet romney is still considered an under